The problem area that we are pursuing in our research represents the translation of external signals into significant reproductive events. We are concerned with experimental analysis of the hierarchical sequence of control of reproduction in the mammal and bird which flows as follows: environment controls hypothalamus controls anterior pituitary controls gonad controls reproductive functions (e.g., spermatogenesis, implantation). Our research laboratories represent a critical mass of technical and conceptual talent coordinated for a multilevel attack on the general problem of signal processing in reproductive control. Menaker is investigating the role of circadian rhythms and associated levels of LH and FSH in the control of reproduction in the hamster. Bronson is concerned with pheromones and hormonal and behavioral responses to pheromones in the immature female mouse, with special reference to the control of puberty. Desjardins is investigating the respective roles of exteroceptive factors and testicular androgens in the regulation of testis function (spermatogenesis). Jacobson is concerned with the embryonic origins and developmental positions which bring the adenohypophysis into the proximity and control of the hypothalamus. Hamilton's research deals with the subcellular actions of estrogen in regulating uterine growth and development to the implantation state.